Definition of Tranquilizer

William C. Shiel Jr., MD, FACP, FACR

Dr. Shiel received a Bachelor of Science degree with honors from the University of Notre Dame. There he was involved in research in radiation biology and received the Huisking Scholarship. After graduating from St. Louis University School of Medicine, he completed his Internal Medicine residency and Rheumatology fellowship at the University of California, Irvine. He is board-certified in Internal Medicine and Rheumatology.

Tranquilizer: In pharmacology, a drug that calms and relieves anxiety. The first tranquilizer, chlordiazepoxidehydrochloride (brand name: Librium), received FDA approval in 1960. Tranquilizers range in potency from mild to major, with increasing levels of drowsiness occurring as potency increases. They are prescribed for a wide variety of conditions but are used primarily to treat anxiety and insomnia. Most tranquilizers are potentially addictive, particularly those in the benzodiazepine family.